Critical Kush Appraisal

Hello. This is the end of week 2 and the beginning of week 3 of veg. About 3 days ago, when I last watered, I saw the lower or first leaf had some brown spots on it. I thought I had got some mixed nutrient on it. I went in today to get pictures and saw it had gotten worse. I think I'll ask a grow question and see what others think. Other than that, things are doing well in here. It's getting cold in the basement now. I have the exhaust fan on as low as it will go. It makes negative pressure in the basement, so we don't smell it upstairs unless it really strong-smelling pot. We have wood heat upstairs, but just grow room lights to heat up the basement. I've had the heater on through the plant's nights to keep them warm. Keep Growing Straight. Chuck.